CN112938081B

CN112938081B - Compression-resistant packaging box

Info

Publication number: CN112938081B
Application number: CN202110095567.1A
Authority: CN
Inventors: 邵兴荣; 张�杰; 郑杨; 沈球国; 王融彬
Original assignee: Yiwu Technology Co ltd
Current assignee: Yiwu Technology Co ltd
Priority date: 2021-01-25
Filing date: 2021-01-25
Publication date: 2021-11-12
Anticipated expiration: 2041-01-25
Also published as: CN112938081A

Abstract

The invention provides a compression-resistant packing box body which comprises a box body and a box cover, wherein the box body and the box cover are both made of specific foamed polypropylene EPP materials. The polypropylene particles and the foaming agent with specific components are conveyed into a pressure soaking tank, a specific material pressing process with four stages of pressurization, pressure relief and pressure maintaining is adopted, the foaming agent and the polypropylene are fully mixed, and then are washed by upper and lower steam, the transverse steam penetrates through the tank to uniformly heat and expand the raw materials, the melt strength is high, the formed foam network is continuous, and the compression resistance and the falling resistance of the tank are improved due to the packaging tank body made of the material, the mechanical strength is high, the service life of the tank body is prolonged, the cost is low, and the processing is easy.

Description

Compression-resistant packaging box

Technical Field

The invention relates to the technical field of logistics transportation packaging equipment, in particular to a compression-resistant packaging box body.

Background

After the existing products are processed and produced, the products are usually protected and packaged by adopting foam plastic products. Need adopt the bubble of preventing static to high-tech electronic product and mould the goods and pack, also have the requirement to the hardness of bubble moulding goods simultaneously to prevent the influence of static to the performance of high-tech electronic product, can avoid external impact force to the destruction of high-tech electronic product simultaneously. At present, in the field of packaging, foamed polystyrene, foamed polyurethane, foamed polyethylene and other foamed plastic materials are mainly used, but the foamed polystyrene and the foamed polyurethane can cause serious pollution to the environment in the use process, isocyanate residues harmful to human bodies exist in the foaming process of the foamed polyurethane, the foamed polyurethane cannot be recycled repeatedly, and chlorofluorocarbon compounds or butane can be generally used in the foaming process of the foamed polystyrene, so that the foamed polystyrene is difficult to degrade and is easy to cause white pollution. The foamed polyethylene plastic has lower hardness, and the maximum use temperature is 80 ℃. The foamed polypropylene EPP is an environment-friendly material, is nontoxic and harmless in the manufacturing process, can be recycled, has high use temperature, is a high-crystallization polymer/gas composite material with excellent performance, and becomes the fastest-growing environment-friendly novel compression-resistant buffering heat-insulating material at present. However, the existing foamed polypropylene EPP material has low compression strength, low hardness and easy deformation, and needs to overcome the defects of poor welding, unstable performance, easy deformation and the like of the foamed polypropylene EPP material in the molding process and improve the welding rate and the density stability of a foamed polypropylene EPP box product.

Disclosure of Invention

The invention aims to provide a compression-resistant packaging box body which is made of a foamed polypropylene EPP material, adopts a specific composition and a specific production process and is used for solving the problems of general antistatic property, insufficient compression strength, unstable performance, easy deformation and the like of the packaging box body in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a compression-resistant packing box, includes box and case lid, its characterized in that, the box has the holding chamber, the case lid covers on the box, the box with the case lid is all made by expanded polypropylene EPP material, the production technology of expanded polypropylene EPP material includes following step:

(1) raw material polypropylene particles and a foaming agent are sent to a pressure soaking tank through a feeding system and are processed through specific material pressing process parameters, and the specific material pressing process comprises the following steps:

the first stage is as follows: applying pressure of 0.05 MPa-0.1 MPa to the raw materials in the soaking tank, wherein the pressing time is 35-45 minutes;

and a second stage: after the first material pressing is finished, increasing the pressure to 0.3-0.4MPa, and pressing for 180-200 minutes;

and a third stage: after the second material pressing is finished, reducing the pressure to 0.2-0.25MPa, and pressing for 100-120 minutes;

a fourth stage: after the third material pressing is finished, reducing the pressure to 0.1-0.15MPa, and pressing for 60-70 minutes;

(2) after the raw material pressing process is finished, the raw material is conveyed into a material cylinder of a forming machine through a material pipe conveying system, a sensor monitors the content of the raw material in the material cylinder in real time in the process, a valve is automatically opened after the content of the raw material is lower than a set amount, and the raw material enters the material cylinder;

(3) the raw materials are precisely fed into a forming die cavity from a material cylinder through a material gun, and are subjected to hot plastic forming after being heated at high temperature by steam;

(4) after falling off from the die, the product is placed in a special drying vehicle and is packaged and delivered after being dried.

The formula of the polypropylene particles comprises the following components in parts by weight: 80-95 parts of terpolymer of propylene, ethylene and 1-pentene, 5-10 parts of polyethylene octene elastomer, 5-10 parts of glycidyl methacrylate grafted polypropylene, 2-5 parts of silicon dioxide, 0.1-0.3 part of silane coupling agent, 0.5-2 parts of aromatic amide nucleating agent and 1-2 parts of antistatic agent.

The aromatic amide nucleating agent is N, N dicyclohexyl terephthalamide, N-dicyclohexyl phthalic diamide, N-dianiline adipamide and the like, the silane coupling agent is KH550, KH560 or KH602, and the antistatic agent is N, N-dihydroxyethyl octadecylamine.

The terpolymer of propylene, ethylene and 1-pentene has a melting point of less than 140 ℃, a molecular weight distribution Mw/Mn of 5-25 and a melt index of 5-10g/10 min. The polyethylene octene elastomer is dispersed in the propylene copolymer, so that the toughness of the propylene copolymer can be improved, and the good impact resistance of the product can be ensured. The silicon dioxide can not only increase the strength of the melt and improve the rigidity, but also has high heat conductivity coefficient, can quickly transfer heat and save the steam consumption. The glycidyl methacrylate grafted polypropylene is used as a compatilizer, the compatibility among the components is adjusted, the silane coupling agent improves the dispersibility, and the good compatibility can ensure the growth density and the integrity of the cells. The foaming ratio of the foaming polypropylene is 15 to 50 times, and the density is 0.03 to 0.07g/cm³. The foaming agent is a supercritical nitrogen fluid,

wherein, the step (3) comprises the following steps: a. steam scouring: opening a steam inlet valve above the steam chamber and a condensed water discharge valve below the steam chamber to flush the steam from top to bottom so as to discharge air out of the steam chamber and discharge the condensed water;

b. transverse steam: the steam is swept from one side of the steam chamber to the raw material, penetrates through the raw material and then reaches the other side of the steam chamber and is sprayed out;

c. pressure maintenance: after the steam is transversely introduced, the temperature in the mold can generally reach more than 140 ℃, an upper steam inlet valve is opened, a lower condensed water discharge valve is closed, the pressure gradually reaches the peak value of 0.9-1.5MPa, and then the pressure is kept for 20-50 s;

d. and (3) cooling and stabilizing: cooling water spraying and vacuum negative pressure waste heat absorbing are adopted to reduce the temperature of the mold to about 50-70 ℃ so as to ensure smooth demolding of the product;

e. and (6) demolding.

The invention has the following beneficial effects: the packing box body is made of the foamed polypropylene EPP material, adopts a formula with specific composition content, has high melt strength, good compatibility, uniform dispersion and good heat conduction, ensures the growth density and integrity of foamed cells, has good antistatic effect, does not contain toxic substances in the production process, and is environment-friendly. And a specific material pressing process, namely a specific material pressing process in four stages of pressurization, pressure relief and pressure maintaining, can enable the foaming agent to be fully soaked in the polypropylene, so that uniform foaming is facilitated, the material density is uniform, and the overall material performance is stable. And then the heat is quickly transferred by washing with upper and lower steam and penetrating through transverse steam, the polypropylene is uniformly melted, expanded and bonded, and finally the obtained product has uniform and complete foam pores, high foaming ratio and difficult deformation. The gas retained in the foam holes absorbs energy, so that the excellent compression-resistant buffering effect is provided, the filler is well fixed in the foaming forming body during uniform expansion to form a continuous network, the excellent surface appearance and rigidity are provided, and the use requirement of the packaging box body is met.

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the technical solutions in the present application will be clearly and completely described below with reference to the embodiments, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. Other embodiments, which can be derived by one of ordinary skill in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

the first stage is as follows: applying pressure of 0.05MPa to the raw materials in the soaking tank, wherein the pressing time is 35 minutes;

and a second stage: after the first pressing is finished, increasing the pressure to 0.3MPa, and pressing for 180 minutes;

and a third stage: after the second pressing is finished, reducing the pressure to 0.2MPa, and pressing for 100 minutes;

a fourth stage: after the third pressing is finished, reducing the pressure to 0.1MPa, and pressing for 60 minutes;

The foaming agent is supercritical nitrogen fluid, and the formula of the polypropylene particles comprises the following components in parts by weight: 80 parts of terpolymer of propylene, ethylene and 1-pentene, 5 parts of polyethylene octene elastomer, 5 parts of glycidyl methacrylate grafted polypropylene, 2 parts of silicon dioxide, KH 5500.1 parts of silane coupling agent, 0.5 part of N, N-dicyclohexyl terephthalamide and 1 part of N, N-dihydroxyethyl octadecylamine.

The step (3) comprises the following steps: a. steam scouring: opening a steam inlet valve above the steam chamber and a condensed water discharge valve below the steam chamber to flush the steam from top to bottom so as to discharge air out of the steam chamber and discharge the condensed water;

c. pressure maintenance: after steam is transversely introduced, an upper steam inlet valve is opened, a lower condensed water discharge valve is closed, the pressure gradually reaches the peak value of 0.9MPa, and then the pressure is kept for 20 s;

d. and (3) cooling and stabilizing: cooling water spraying and vacuum negative pressure waste heat absorption are adopted, so that the temperature of the mold is reduced to about 50 ℃, and smooth demolding of the product is ensured;

e. and (6) demolding.

The foaming ratio of the foamed polypropylene material prepared by the method is 17.2 times, and the density is 0.067g/cm³The foam cells are uniform and the appearance is good, the compression strength MPa (25% deformation) measured by the ISO844 test method is 1.2, and the tensile strength measured by the ISO1798 test method is 7.8 MPa.

Example 2

the first stage is as follows: applying pressure of 0.1MPa to the raw materials in the soaking tank, wherein the pressing time is 45 minutes;

and a second stage: after the first pressing is finished, increasing the pressure to 0.4MPa, and pressing for 200 minutes;

and a third stage: after the second material pressing is finished, reducing the pressure to 0.25MPa, and pressing for 120 minutes;

a fourth stage: after the third pressing is finished, reducing the pressure to 0.15MPa, and pressing for 70 minutes;

The foaming agent is supercritical nitrogen fluid, and the formula of the polypropylene particles comprises the following components in parts by weight: 95 parts of propylene, ethylene and 1-pentene terpolymer, 10 parts of polyethylene octene elastomer, 10 parts of methacrylic acid glycidyl ether grafted polypropylene, 5 parts of silicon dioxide, KH 5500.3 parts of silane coupling agent, 2 parts of N, N dicyclohexyl terephthalamide and 2 parts of N, N-dihydroxyethyl octadecylamine.

c. pressure maintenance: after the steam is transversely introduced, opening a steam inlet valve at the upper part, closing a condensed water discharge valve at the lower part, gradually reaching the peak value of 1.5Mpa, and then keeping the pressure for 50 s;

d. and (3) cooling and stabilizing: cooling water spraying and vacuum negative pressure waste heat absorbing are adopted, so that the temperature of the mold is reduced to about 70 ℃, and smooth demolding of the product is ensured;

e. and (6) demolding.

The foaming ratio of the foamed polypropylene material prepared by the method is 45 times, and the density is 0.034g/cm³The foam cells are uniform and the appearance is good, the compression strength MPa (25% deformation) measured by the ISO844 test method is 0.4, and the tensile strength measured by the ISO1798 test method is 4.7 MPa.

Comparative example 1

Compared with the example 1, the step (1) is that raw material polypropylene particles and foaming agent are sent to a pressure impregnation tank through a feeding system, the pressure is directly applied to the raw material in the impregnation tank to 0.3MPa, and the raw material is pressed for 375 minutes. The rest is the same as in example 1.

The prepared foaming polypropylene material has the foaming ratio of 14.2 times and the density of 0.087g/cm³The cells were not uniform and the appearance was poor, the compressive strength MPa (25% deformation) measured by ISO844 test method was 0.7, and the tensile strength measured by ISO1798 test method was 5.4 MPa.

Comparative example 2

In comparison with example 1, step (1) was to feed raw polypropylene particles and a foaming agent into a pressure impregnation tank via a feed system, apply a pressure of 0.1MPa to the raw material in the impregnation tank for a pressing time of 75 minutes, and then increase the pressure to 0.3MPa for 300 minutes. The rest is the same as in example 1.

The prepared foamed polypropylene has the foaming ratio of 14.9 times and the density of 0.074g/cm³The cells were not uniform and the appearance was poor, the compressive strength MPa (25% deformation) measured by ISO844 test method was 0.9, and the tensile strength measured by ISO1798 test method was 5.9 MPa.

Comparative example 3

Compared with the embodiment 1, the step (3) does not carry out the steps of steam scouring and transverse steam penetration, the upper steam inlet valve is directly opened, the lower condensed water discharge valve is closed, the pressure gradually reaches the peak value of 0.9MPa, and then the pressure is maintained for 20 s. The rest is the same as in example 1.

The prepared foaming polypropylene material has the foaming ratio of 14.5 times and the density of 0.076g/cm³The cells were not uniform and the appearance was poor, the compressive strength MPa (25% deformation) measured by ISO844 test method was 0.8, and the tensile strength measured by ISO1798 test method was 5.7MPa。

Comparative example 4

Compared with the example 1, the formula of the polypropylene particle comprises the following components in parts by weight: 80 parts of terpolymer of propylene, ethylene and 1-pentene, 5 parts of polyethylene octene elastomer, 2 parts of silicon dioxide and 1 part of N, N-dihydroxyethyl octadecylamine. The rest is the same as in example 1.

The prepared foaming polypropylene material has the foaming multiplying power of 17.6 times and the density of 0.063g/cm³However, the cells are not complete enough to form a network with poor continuity, a compressive strength MPa (25% deformation) of 0.7 as determined by ISO844 test method and a tensile strength of 4.5MPa as determined by ISO1798 test method.

The present invention is not limited to the above exemplary embodiments, and any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a compression-resistant packing box, includes box and case lid, its characterized in that, the box has the holding chamber, the case lid covers on the box, the box with the case lid is all made by expanded polypropylene EPP material, the production technology of expanded polypropylene EPP material includes following step:

(4) after falling off from the die, the product is placed in a special drying vehicle, and is packaged and delivered after being dried;

the formula of the polypropylene particles comprises the following components in parts by weight: 80-95 parts of terpolymer of propylene, ethylene and 1-pentene, 5-10 parts of polyethylene octene elastomer, 5-10 parts of glycidyl methacrylate grafted polypropylene, 2-5 parts of silicon dioxide, 0.1-0.3 part of silane coupling agent, 0.5-2 parts of aromatic amide nucleating agent and 1-2 parts of antistatic agent, wherein the foaming agent is supercritical nitrogen fluid;

c. pressure maintenance: after the steam is transversely introduced, opening a steam inlet valve at the upper part, closing a condensed water discharge valve at the lower part, enabling the pressure to gradually reach the peak value of 0.9-1.5MPa, and then keeping the pressure for 20-50 s;

d. and (3) cooling and stabilizing: cooling water spraying and vacuum negative pressure waste heat absorbing are adopted to reduce the temperature of the mold to 50-70 ℃ so as to ensure smooth demolding of the product;

e. and (6) demolding.

2. The compression-resistant packaging box as claimed in claim 1, wherein the aromatic amide-based nucleating agent is N, N dicyclohexylterephthalamide, N-dicyclohexylphthalimide or N, N-diphenylaminohexanediamide.

3. The compression-resistant packaging case as claimed in claim 1, wherein the temperature inside the mold reaches 140 ℃ or higher after the steam is introduced.

4. The compression-resistant packaging container as claimed in claim 1, wherein the silane coupling agent is KH550, KH560 or KH 602.

5. The compression-resistant packaging case as claimed in claim 1, wherein the antistatic agent is N, N-dihydroxyethyl octadecylamine.